计算【1/(x-2)】-【1/(x+2)】+【(x2-4x)/(x2-4)】

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计算【1/(x-2)】-【1/(x+2)】+【(x2-4x)/(x2-4)】
计算【1/(x-2)】-【1/(x+2)】+【(x2-4x)/(x2-4)】

计算【1/(x-2)】-【1/(x+2)】+【(x2-4x)/(x2-4)】
原式=[(x+2)-(x-2)]/(x+2)(x-2)+(x2-4x)/(x+2)(x-2)
=4/(x+2)(x-2)+(x2-4x)/(x+2)(x-2)
=(x2-4x+4)/(x+2)(x-2)
=(x-2)2/(x+2)(x-2)
==(x-2)/(x+2)

=π =0 =213123。31411234123421341234

=[x+2-(x-2)]/[(x+2)(x-2)]+[x2-4x)]/[(x+2)(x-2)]
=(x2-4x+4)/[(x-2)(x+2)]
=[(x-2)(x-2)]/[(x-2)(x+2)]
=(x-2)/(x+2)